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Advances in Physical Chemistry
Volume 2014, Article ID 879608, 14 pages
http://dx.doi.org/10.1155/2014/879608
Research Article

Ruthenium(III) Catalysis in Perborate Oxidation of 5-Oxoacids

1Research and Development Centre, Bharathiar University, Coimbatore 641 046, India
2The Department of Chemistry, Arignar Anna Government Arts College, Cheyyar 604 407, India
3Department of Chemistry, Dr. Ambedkar Government Arts College, Chennai 600 039, India
4Department of Chemistry, Presidency College, Chennai 600005, India

Received 16 May 2014; Revised 2 August 2014; Accepted 3 August 2014; Published 24 August 2014

Academic Editor: Taicheng An

Copyright © 2014 S. Shree Devi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Ruthenium(III) catalyzes perborate oxidation of substituted 5-oxoacids in acidic solution. The catalyzed oxidation is first order with respect to the oxidant and catalyst. The rate of ruthenium(III) catalyzed oxidation displays the Michaelis-Menten kinetics on the reductant and is independent of [H+] of the medium. Hydrogen peroxide is the reactive species of perborate and the kinetic results reveal formation of ruthenium(III) peroxo species-5-oxoacid complex. Electron-releasing substituents accelerate the reaction rate and electron-withdrawing substituents retard it. The order of reactivity among the studied 5-oxoacids is p-methoxy   p-methyl > p-phenyl > −H > p-chloro > p-bromo > m-nitro. Activation parameters are evaluated using Arrhenius and Eyring’s plots. A mechanism consistent with the observed kinetic data is proposed and discussed. A suitable rate law is derived based on the mechanism.